Now that, would be interesting. The National library services in the US is the only one of it's kind to drm protect their files as far as I know. RFB&D and bookshare not-with-standing. Since most of the world uses unprotected mp3 marked up with xml and other open standards to create daisy books, Adding the ability to use them to rockbox would be highly complementary.

Add to that the availability of commercial daisy books from publishers such as brilliance audio, and you have a feature that can be enjoyed by many audiobook lovers, not only blind people.